<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>写出⼀个 1 到 10 的数组，少写⼀个数字，利⽤函数将少写的数字找出来</title>
</head>

<body>
  <script>
    var miss = function (nums) {
      var n = 0,
        len = nums.length;
      for (var i = 0; i < len; i++) {
        console.log(nums[i]);
        n += nums[i];
      }
      console.log((1 + len), (len / 2), n);
      return (1 + len) * (len / 2) - n;
    };
    console.log(miss([0, 1, 2, 3, 4, 5, 6, 7, 8, 10]));
  </script>
</body>

</html>